Ballistically actuated detonating device for an explosive charge



INVENTOR.

July 16, 1968 R J. ARMANTRQUT 3,392,628

BALLISTICALLY ACTUATED DETONATING DEVICE FOR AN EXPLOSIVB CHARGE Filed Sept. 12. 1966 In 2 w 3 3 5: 1: mam: q I\ ROBERT J. ARMANTROUT BY 5 Z i I f BALLISTICALLY ACTUATED DETONATING DEVICE FOR AN EXPLOSIVE CHARGE Robert J. Armantrout, Lake Forest, NJ., assignor to Hercules Incorporated, Wilmington, Del., a corporation of Delaware Filed Sept. 12, 1966, Ser. No. 578,658 4 Claims. (Cl. 89-1) ABSTRACT OF THE DISCLOSURE The present invention relates to a device for positioning and for detonating an explosive charge and comprises a conduit upon the one end of which the charge is secured in alignment with the bore of the conduit and upon the other end of which there is a breech mechanism for firing a bullet longitudinally through the bore to impact against and thus detonate the charge. As disclosed, the charge is positioned by the conduit at the focal point of a parabolic recoil mass of a seismological apparatus while the breech mechanism is located externally of the apparatus and adapted to be fired remotely.

The present invention relates to means for initiating detonation of an explosive charge and relates in particular to the use of a ballistic projectile for effecting detonation of an explosive charge.

The objects of this invention are to provide an initiator or a means for effecting detonation of an explosive charge, which means is inexpensive, simple in construction, easy to operate at a relative fast firing rate, is safe and has a high reliability factor. Other objects of this invention will be apparent from an understanding of the preferred embodiment of the invention hereinafter disclosed.

The above objects have been achieved in accordance with this invention by an initiator or detonating device in which a ballistic projectile, and particularly, a conventional rifle bullet, such as a gallery round of .22 caliber short ammunition, is fed into the explosive charge whereby the impact of the bullet against as Well as the friction and heat of the bullet passing into the explosive charge initiates detonation. The initiator or detonating device in accordance with this invention is particularly useful in detonating seismic charges used in geophysical surveys.

With the above and other objects in view, a preferred embodiment of the invention is hereinafter described in connection with the accompanying drawings, in which:

FIG. 1 is a schematic illustration of an assembled initiator and explosive charge constructed in accordance with the present invention.

FIG. 2 is a view, partly broken away, illustrating a conventional round of .22 caliber short rifle ammunition which is adapted to be used in the initiator of FIG. 1.

FIG. 3 is a sectional view of one form of a Seismological device for geophysic exploration with which the apparatus of FIG. 1 is particularly useful.

With reference to the drawings, there is illustrated in FIG. 1 a conventional bolt-action breech mechanism 1 such as that which may be used in a .22 caliber rifle. The illustrated mechanism 1 includes a manually actuated bolt 2 for opening and closing the firing chamber and a firing mechanism that includes a trigger that is tripped by a firing lever 3 adapted to be actuated remotely by a lanyard 4. The barrel 5 of the breech mechanism 1 is short and has a bore *6 and external threads 7 at the free end thereof on which may be threaded a choke 8. The choke 8 has a through bore 9 communicating with the bore 6 of the barrel 5 and vents 10 in the sides to dissipate the backpressure from the explosion and thus protect the breech nited States Patent 9 r 3,392,628 Patented July 16, 1968 mechanism 1 from damage. The choke 8 includes a short barrel 11 having a bore 12 and external threads 13 on which is threaded a pipe-like conduit 14. The conduit 14 has an impervious or water-tight side Wall and a bore 15 which, together with the bore 12 of the barrel 11 of the choke 8, is aligned With the bore 6 in the barrel 5 of the breech mechanism 1 when the parts are assembled. The diameter of the bores 12 and 15 is larger than the diameter of the bore 6 by an amount sufficient to insure free flight of the projectile from the bore 6 through the bores 9 and 12 of the choke 8 and the bore 15 of the conduit 14.

At the end of the conduit 14 opposite from the breech mechanism 1, there is mounted an adapter 16 having a bore 17 and a tapered end 18 leading from the free end of the adapter onto a mounting surface 19. The breech mechanism 1, choke 8, conduit 14 and adapter 16 constitute the indicator of detonating device for an explosive cartridge 20, which in turn comprises a tube 21 of paper or other suitable material having an internal diameter substantially equal to the external diameter of the mounting surface 19 of the adapter 16 and a small explosive 0r seismic charge 22 partially filling the tube 21 at the free end thereof and spaced from the end of the adapter 16. The cartridge 20 is designed to be pressed onto and frictionally held on the adapter 16, the tapered surface 18 serving to guide the end of the tube 21 onto the mounting surface 19 which may be fitted With a rubber O-ring 23 to hold the tube 21 more securely and to provide a watertight connection. While the tube 21 is preferably cylindri cal, it will of course be apparent that other specific shapes could be used.

In operation, the breech mechanism 1 is adapted to fire a round of conventional rifle ammunition such as the .22 caliber short rifle cartridge 24 illustrated in FIG. 2, and which consists of a case 25, an explosive propellant 26 and a bullet or projectile 27. When fired, the bullet 27 travels at a high velocity from the bore 6 of the barrel 5, successively through the bores 9 and 12 of the choke 8, the bore 15 of the conduit 14, the bore 17 of the adapter 16, and through the tube 21 to impact against the explosive 22 and thereby detonate the same.

In FIG. 3, there is illustrated a seismological device 28 with which the ballistically detonated explosive charge of this invention is particularly useful. The device 28 comprises a heavy steel base plate 29 and a cylindrical side wall 30 which is reinforced at its juncture with the base plate 29 by an internal collar 31 and an external collar 32. At its upper end, the side wall 30 has an outwardly directed flange 33 on which the flange 34 of a domeshaped cover 35 is resiliently held by spring-pressed bolts 36. The device 28 is filled with water and is provided internally with a heavy steel parabolic recoil mass 37 that rests on the base plate 29 and has an opening 38 centrally thereof. There is also an opening 39 centrally of the cover 35. In use, the assembled cartridge 20 and initiator or detonating device is mounted on the cover 35 as by means of a mounting plate 40 that is adjustably secured along the conduit 14. When the plate 40 is mounted on the cover 35, the conduit 14 extends downwardly through the opening 39 in the cover 35 and the opening 38 in the recoil mass 37 to position the cartridge 20 with the seismic charge 22 at the focal point of the recoil mass 37. The choke 8 and the breech mechanism 1 are then disposed above the cover 35. Either before or after the assembly is mounted on the cover 35, a round of .22 caliber short ammunition is loaded in the usual manner into the firing chamber of the breech mechanism 1. When the trigger is then tripped by pulling the lanyard 4, this round is fired and in turn detonates the explosive 22.

When the explosive 22 is detonated in the device of FIG. 3, the force of the explosion is concentrated onto 3 the plate 29, which is thus violently impacted against the earth to establish vibrations. The echos of these vibrations are recorded by geophones or other instruments and give an indication of the underlying geophysical formations.

In addition to the seismological device described above, the present invention has utility in other fields, e.g., in metal-forming operations.

The present invention is not, of course, limited to use with any specific projectile or any specific explosive material although there is a dependent relation between the energy of the projectile and the sensitivity of the explosive. With explosives that are highly sensitive to shock and impact, a projectile of relatively low mass and low velocity will effect detonation. However, with an insensitive explosive, a projectile of increased mass and/or increased velocity will be required to effect detonation. Normally, a .22 caliber gallery round short rifle cartridge at a range of forty-five inches for example from the barrel to the target will have sufficient energy to detonate consistently a gelatine type dynamite having a nominal strength of about 65%, such as the explosive sold by Hercules Incorporated under the trademark Gelamite 1.

One of the significant advantages of the assembly of the explosive and detonating device in accordance with this invention and in use in the Seismological device of FIG. 3 is that it can be quickly loaded into and is automatically positioned at exactly the desired spot in the explosion chamber. In order to fire a shot, the explosive cartridge 20 is pressed onto the adapter 16 and the assembly is then inserted through the hole 39 in the cover 35 and the hole 38 in the recoil mass 37. With the mounting plate 40 adjusted endwise of the conduit 14, the charge 22 is automatically positioned at the focus of the recoil mass 37 when the plate 40 rests on the cover 35. At the same time, the interior of the cartridge 20 is mounted in a water-tight fashion on the end of the conduit 14 whereby, when the charge is located at its operative position, which is under the level of the water in the device, there is no water leaking into the interior of the cartridge 20 or the conduit 14 and thus there is no water to damage the explosive 22 or to interfere with the free flight of the projectile into the explosive 22. The fact that the present invention is useful for positioning as well as detonating explosives under water is a further advantage.

A further advantage of the present invention is that it affords economical as well as effective and rapid-fire detonation of explosive charges. A round of .22 caliber short rifle ammunition is not only very inexpensive, but is also universally available. Thus, there is no necessity for shipping both the explosive and the initiator therefor, but rather, the explosive can be shipped by itself and the initiator, i.e., a round of .22 caliber short ammunition, can usually be obtained locally or is otherwise readily available separately. It will also be apparent that magazine loading of the breech mechanism 1 and of the explosive charge can be effected, which thus increases the firing rate and is of advantage in conducting seismic mappings or in manufacturing processes involving explosive forming of metal. Because of the high impact that is developed at the necessary range by a round of conventional .22 caliber rifle ammunition, a relatively insensitive explosive can be used, thus increasing the safety margin and also permitting more rapid and mechanical handling.

What I claim and desire to protect by Letters Patent is:

1. In combination, an explosive cartridge and a device for supporting and for ballistically detonating the same, said cartridge comprising a tube and an explosive charge filling one end of said tube, said device for supporting and ballistically detonating said cartridge comprising a conduit having a 'bore through which a bullet is adapted to pass in free flight, a breech mechanism at one end of said conduit for firing a round of rifle ammunition including a bullet and a propelling charge and for directing the bullet lengthwise of the bore in said conduit, means for securing said cartridge to the end of said conduit opposite from said breech mechanism and for positioning the explosive charge in alignment with the bore of said conduit whereby a bullet passing through said bore from said breech mechanism will strike the explosive charge and detonate the same, said securing means comprising an adapter on said conduit for cooperating with the unfilled end of said cartridge, and mounting means for supporting said conduit with said cartridge in detonating position.

2. A ballistically actuated initiating device in accordance with claim 1 in which said adapter has a mounting surface and the unfilled end of said tube has an internal dimension substantially equal to the external dimension of said mounting surface whereby the means for securing said tube on said conduit comprises a force-fit of the unfilled end thereof on the mounting surface of the adapter.

3. A ballistically actuated initiating device in accordance with claim 2 in which said conduit has an impervious side wall and there is provided a water-tight connection between said adapter and said explosive charge.

4. A ballistically actuated initiating device in accordance with claim 1 in which said mounting means comprises a mounting plate secured externally to said conduit for adjustment lengthwise thereof.

References Cited UNITED STATES PATENTS 1,277,669 9/1918 Viven et al 421 1,375,463 4/1921 McAdam 421 2,415,803 2/1947 Abell 421 2,432,539 12/1947 Olsen 421 2,963,943 12/1960 Cutts 4279 3,127,691 4/1964 Moore 421 3,277,785 10/1966 Clayton 89l BENJAMIN A. BORCHELT, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Robert J. Armantrout It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 42, "fed" should read fired Column 2, line 17, "indicator of" should read initiator or Signed and sealed this 2nd day of December 1969.

(SEAL) Attest:

Edward M. Fletcher, Jr.

Attesting Officer Commissioner of Patents 

